diff --git a/subiquity/models/filesystem.py b/subiquity/models/filesystem.py
index a42073ac..47803059 100644
--- a/subiquity/models/filesystem.py
+++ b/subiquity/models/filesystem.py
@@ -575,6 +575,8 @@ class Raid(_Device):
     def ok_for_raid(self):
         if self._fs is not None:
             return False
+        if len(self._partitions) > 0:
+            return False
         return True
 
     ok_for_lvm_vg = ok_for_raid